The purpose of this clinical investigation is to gather sufficient clinical and radiographic data to permit valid scientific comparisons between treatment and control group outcomes. The treatment group/device for this study is the ASR™-XL Acetabular Cup System, and the control group/device is the Pinnacle™ Cup System w/ the 28mm or 36mm ULTAMET™ metal liner. The study objective will be achieved by way of treatment group selection, treatment administration, and management of participating study Subjects.